A sum of graphs f(x) and g(x) is a graph which ordinate is the sum of the ordinate f(x) and the ordinate of g(x). It is defined as f(x) + g(x). A difference, product and ratio of the graphs are constructed in the same manner.
Note that a graph of f(x) / g(x) may have infinitive value at some point x if g(x) = 0.
In this model you can enter a functions in the text fields f(x) (blue graph) and g(x) (red graph), choose a type of resulted graph (green graph) and obtain all these graphs.